Bowling pin



United States Patent Office 3,048,400 Patented Aug. 7, 1962 3,048,400BUWLING lllN Mark M. Friedman, Inglewood, Calif., assignor to PacificMolded Pulley Company, Inc, Gardena, Calif., a corporation of CaliforniaFiled Dec. 6, 1057, Ser. No. 701,057 1 Claim. (Cl. 273-82) Thisinvention relates to bowling pins, more particularly to bowling pinsmolded of plastic material. Bowling pins now in common use are made ofmaple, or maple coated with a vinyl plastic film. The deficiencies ofwood, even an excellent hard wood such as maple, have long beenrecognized. However, the game of bowling has been dependent upon theparticular manner in which the bowling pins bounce and scatter whenstruck by a bowling ball. The bowling pin must have a bounce whichclosely approaches that of a maple bowling pin in magnitude; that is,the pattern of the pin fall must be close to that of a wooden bowlingpin. Otherwise the bowling pins would not move in the variouscharacteristic patterns when struck by the bowling ball moving throughthe different typical paths down the bowling alley, and the resultingscore would differ. Furthermore, the sound should approach closely tothe characteristic sound produced by maple pins when struck by thebowling ball in order to be acceptable to the bowler.

It is well known that slight changes in the course taken by the bowlingball and the resulting slight changes in the point of initial impacthave a marked effect on the number of pins knocked down. The dispersalpatterns taken by the bowling pins actually struck by the bowling balland those struck by other bowling pins are extremely complex, andconsequently easily altered by any change in the physical properties ofthe bowling pin.

It is well known by bowling alley operators, but less well known bybowlers, that even new wooden pins vary in weight and bounce, and thatas the bowling pins become worn, chipped, and otherwise damaged, and arerefinished or repaired, their physical properties vary substantiallymore.

The good condition life of a wooden bowling pin is relatively short. Thewooden bowling pin is damaged to the point of needing repair afterapproximately 500 lines (i.e., 5000 engagements by the bowling ball).Obviously its physical characteristics, such as its degree and directionof bounce, are adversely aifected long before 500 lines. It is the usualpractice to repair and recondition the wooden bowling pins after each500 lines, and 2000 lines represent about the maximum useful life. Butas indicated, during much of this life the bowling pin has suffered suchchange in its character that the bowlers game is adversely affected. Thepatron or bowler is not usually aware of this because he is too far fromthe bowling pins to inspect them, and there is little or no change insound or change readily observable from the patrons end of the alley tocall his attention to the deteriorated quality of the bowling pin.

Thus, it is not a solution to the problem to make a plastic bowling pinwhich is better than a wooden bowling pin in good condition. Instead,the plastic bowling pin must have such characteristics that, when usedon an alley neighboring an alley having wooden bowling pins in goodcondition, the difference in action and sound will not be noticeable tothe patron; otherwise, even though an unbiased scientific test mightshow the plastic bowling pin to be better, the patron will not acceptit.

With the foregoing rsnm of the problem in mind, the objects of thepresent invention include:

First, to provide a plastic bowling pin which duplicates closely theobservable characteristics of a maple bowling pin in good condition,such as to exhibit a comparable bounce, to produce a pattern of pin fallcorresponding closely to a maple bowling pin, and to produce a soundclosely simulating the sound produced by maple bowling pins, when struckby the bowling ball and by each other.

Second, to provide a plastic bowling pin which is capable ofwithstanding impact of a bowling ball and impact from other bowling pinswithout splitting, cracking, or chipping, and which in fact, remains invirtually its initial condition after many hundreds of lines; that is,long beyond the life of a maple bowling pin even though the life of themaple bowling pin is prolonged by repeated reconditioning and repair;thereby providing a bowling pin which, though having a necessarilyhigher initial cost than maple bowling pins, has instead such prolongedlife that the cost per line by the bowling alley operator is materiallyreduced.

Third, to provide a plastic bowling pin which utilizes a novellyconstructed body member and bottom member of different Shore hardness toprovide optimum resilience in the region of impact by a bowling ball,and optimum hardness and strength at the bottom of the bowling pin sothat the stability of the bowling pin is not impaired with use.

Fourth, to provide a plastic bowling pin having a sound chamber andmeans contained therein whereby the bowling pin may be predesigned toproduce a desired sound and exhibit a desired bounce.

With the above and other objects in view, as may appear hereinafter,reference is directed to the accompanying drawings in which:

FIGURE 1 is a longitudinal sectional view of a bowling pin incorporatingthe present invention;

FIG. 2 is a transverse sectional view through 22 of FIG. 1;

FIG. 3 is a transverse sectional view through 33 of FIG. 1;

FIG. 4 is a fragmentary, longitudinal sectional view similar to FIG. 1showing a modified construction;

FIG. 5 is a transverse sectional view through 55 of FIG. 4;

FIG. 6 is a fragmentary, substantially diagrammatical, sectional view ofthe ball-engaging zone of the bowling pin as well as the bowling ball.

The bowling pin includes a body member 1 molded of plastic material.Externally the body member is contoured to define a belly 2, neck 3, andhead 4 of a bowling pin. Internally the body member 1 is provided with alongitudinal bore 5, which is enlarged in the region of the bellyportion '2 to form a cylindrical chamber 6 which converges conically, asindicated by 7, at its upper portion.

Molded or cast within the bore 5 is a reinforcing tube 8, preferablyformed of aluminum, or of glass fabric reinforced plastic. The lower endof the tube projects a short distance within the conical portion 7.Radiating webs 9 extend inwardly from the sides of the conical portion 7to the reinforcing tube 8. The upper end of the bore 5 may be closed bya plug 10.

A bottom member 11 is provided which is also molded of plastic material.The bottom member forms externally a flat base 12 and a conical sideportion 13 which converge upwardly to the lower end of the belly 2 ofthe body member 1. The bottom member 11 includes an integral cylindricalshell 14 which telescopes into the cylindrical chamber 6. i

The body member 1 and bottom member 11 are permanently joined togetherby adhesive or solvent cement 15 applied between the confrontingsurfaces of the cylindrical chamber 6 and the cylindrical shell 14. Inpractice, excess cement upwells above the shell. The bottom a) member 11as well as the cylindrical shell l4 are hollow. The bottom member may beprovided with an internal boss 16 bored to form a center hole or socket17.

Before joining the body member 1 and bottonr member 11, a series ofsound and bounce control disks are inserted. A disk 18 is cemented inthe upper end of the cylindrical portion 6 adjacent the conical portion'7. Two disks 19 and 2d are cemented within the cylindrical shell 14.The disk 19 is located at the upper end of the shell and rests on ashoulder 21. 20 is disposed adjacent the conical lower portion of thebottom member 11. The disks have, respectively, central openings 22, 23,and 24. The second disk 19 is preferably twice as thick as the other twodisks and the opening 22 in the upper disk is preferably larger than theopenings '23 and 24. All of the disks are preferably formed of plywood.

The confronting sides of the disks 19 and 20 are covered with heavypaper or plastic sheet membranes 25 and '26 to divide the lower end ofthe bowling pin into two compartments. These compartments areapproximately half filled with sand or similar granular substance 27.The mobile granular substance lowers the center of gravity and alsoapparently affects the sound as well as bounce and pin pattern. This maybe due to an inertia effect.

An alternative structure is shown in FIGS. 4 and 5. In the constructionhere shown, the plywood disks 18, 19, and 20 are omitted, and insteadthe bottom member 11 is provided with radiating webs or ribs 28 whichjoin at the center to form a core 29. A center hole or recess St} isformed in the bottom end of the core 29. The ribs 28 not only reinforcethe bowling pin but tend to modify the sound. This constructionperformed satisfactorily and was close in behavior to the standardwooden pin; however, not as close as to bounce, pin fall, and especiallysound as the first described structure. Also, as in the first describedstructure, sand or other granular material 27 may be added.

The plastic material utilized in the construction of the bowling pinshould be tough, slightly resilient, and have good impactcharacteristics.

It is desirable that the bottom member 11 be somewhat harder than thebody member 1. It has been found that the bottom member 11 may have aShore D hardness of between and 90. A bottom member having a Shore Dhardness of 72 has given satisfactory service. The Shore D hardness ofthe body member "1 may be between 40 and 70. Body members having a ShoreD hardness of 47 and 57 have given satisfactory service.

A set of twenty bowling pins constructed as shown in FIGS. 4 and 5,wherein the bottom member had a Shore D hardness of 72 and the bodymember a Shore D hardness of 57, was used in test on a bowling alley andsubjected to 1200 lines (a line representing each ten throws of thebowling ball). After this test the bottom members showed no damagewhatsoever; the body members exhibiting a few superficial dents,presumably due to impact by the corners of the bottom members of otherbowling pins. However, the dents were not sufficient to constitutedamage to the bowling pins. By contrast, wooden bowling pins made ofmaple would have withstood only 300 to 500 lines, and thus for the samelength of service would have had to be refinished two or three times.This would have resulted in a detrimental change in weight and dimensionas well as substantial reconditioning expense.

Subsequent tests with the construction shown in FIGS. 1-3 equalled thetest with the bowling pins constructed as shown in FIGS. 4 and 5 insofaras withstanding the loads imposed. However, the sound produced appearedcloser to the sound of wooden pins. This was confirmed by oscillographtests. Still further, especially with the addition of the sand, bounceas well as pin fall seemed to approach remarkably close to the action ofwooden The lower disk T 1, bowling pins. This was confirmed to a largeextent by high speed photographs of the bowling pins when struck bybowling balls in the course of tests on a bowling alley; and also bybounce tests involving pendulum mounting a bowling pin and bowling ball,then striking the pin by the ball with a preselected force. In thisregard, tests were conducted by varying the amount of free sand. Theresulting bounce tests varied from below that of the range expected ofwooden pins When excess sand was used, to above that of such range whenthe sand was omitted.

In spite of the attempts to determine scientifically the action of theplastic bowling pins, there remains a domain which is dependent onsubjective test by the player himself. Repeated tests by bowlers,especially with the construction shown in FIGS. 13, however, seemed toconfirm the more precise tests. For example, the average score over manygames played with the plastic bowling pins and corresponding wooden pinswas well within the statistical variation to be expected if only woodenpins had been used. Again, this was especially true of the constructionshown in FIGS. 1-3.

It will be observed that the cylindrical disks l8 and 19 are centeredsubstantially in the region of impact, that is, the region in which thebowling ball contacts the bowling pin, thus reinforcing the body member1.

The accumulative volume of the cavity or chamber provided within thebowling pin is calculated to compensate for the extra density of theplastic material, so that the completed plastic bowling pin will weighthe same as a wooden or maple bowling pin, and within the AmericanBowling Congress weight limits (2 lbs. 14 oz. to 3 lbs. 10 02.).

Reference is directed to FIG. 6. Wooden bowling pins are, within aboutlines of play, conditioned; that the bowling pin to lift and a betterscatter occurs.

In the case of the plastic bowling pins herein described, noconditioning occurs by reason of engagement by the bowling ball or byinterengagement; consequently, it is preferred to provide a cylindricalarea 31 in the region extending about A" above and below the center lineof the bowling ball 32.

While particular embodiments of this invention have been shown anddescribed, it is not intended to limit the same to the exact details ofthe constructions set forth, and it embraces such changes,modifications, and equivalents of the parts and their formation andarrangement as come within the purview of the appended claim.

What is claimed is: g

A bowling pin formed of molded plastic material, com prising: a bodymember defining externally the belly, neck, and head of a bowling pin,said member having a longitudinal bore enlarged within said bellyportion and continuing upwardly therefrom into said neck portion;reinforcing means in said neck portion; a bottom mem ber including atubular portion arranged initially to telescope within the enlargedportion of said here and be bonded to the walls thereof, said bottommember also including side walls converging from the lower end of saidbody member and a bottom wall completing the external contour of thebowling pin, said body and bottom members defining a closed chamber;sound and bounce control means within said chamber including a pluralityof annular disks formed of wood and transversely disposed in saidchamber, the lower of said disks covered with a membrane to form anupper and a lower compartment; and a mobile material divided betweensaid compartments.

References Cited in the file of this patent UNITED STATES PATENTS1,088,312 Whelan Feb. 24, 1914 1,969,378 McKenzie Aug. 7, 1934 2,166,950German et a1. July 25, 1939 2,517,116

6 2,775,456 Schroeder et a1. Dec. 25, 1956 2,797,923 Dettman July 2,1957 FOREIGN PATENTS 734,679 France Aug. 8, 1932 OTHER REFERENCES ModernPlastics, October 1948, pages 99103 cited. Newspaper clipping from TheGary Post Tribune,

Klinger Aug. 1, 1950 10 Gary, Ind., Mar. 16, 1954, page 1 cited.

